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January 2021 Medium/Longterm Pattern Discussion.


AMZ8990
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Seems like we are losing that big ballyhood cold air, sure hope some type of system gets together for us soon. Looking at models seem like we can't get the system when it's cold enough and when we get the system it warms up. This pattern has been good for east tn and especially parts of oklahoma and texas but all the polar vortex strat hype hasn't bought much cold yet. I know we are just now approaching mid month but nothing solid appears on the horizon and temps don't look that cold and the storms so far have been going south without any nw trends much to speak of. Going to quit the rant weather will do what it's going to do but the models can't figure out what is going on from one run to the next it seems.

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Yes we just need to get something within 5 days while things change within 5 days many times they are not as drastic as models figuring out past 7 days. The good thing in this pattern if we do get a good one it's liable to sneak up on us 3-4 days out of possibly a little sooner. I could see something pop up 3 days out of the blue in the pattern we are in.

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Good write up by MRX this morning about the potential for snow Friday night into Saturday morning and how models are very possibly underdoing the precip that falls as snow. MRX also mentioned there will be no temp issues and all areas will see frozen that see precip.

 

Quote

Yesterday the NBM
didn`t have any POPs in place on Saturday but now it is coming
more in line with the NAM/GFS/ECMWF/CANADIAN which all show an
area of precip moving in late Friday night and into Saturday. This
precip is associated with the broad area of low pressure that
sags further southward into the Ohio River Valley during this
timeframe. With the cold air in place, where there is precip, all
areas will see snow in the Friday night through Saturday morning
timeframe. Some areas will continue to see snow into Saturday
afternoon where cold enough. Now that the NBM has POPs in place,
this yields more confidence in at least some precip occurring so
have slightly increased POPs compared to previous forecast. The
biggest question that remains is how much precip will there
actually be since we will be on the back side of the front. The
forcing is quite strong so it`s possible that we may squeeze out a
little more precip than some of the models are currently showing.
It`s also possible that any areas that get under a good snow band
could pick up some light accumulations early Saturday morning
into Saturday afternoon. Stay tuned to further developments. Snow
showers linger Saturday evening and taper off through the night as
the aforementioned low ejects northeast.

 

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This is the third of these SSW I've watched and I have to say, if this one doesn't do much, it will be the last one I care about. I've seen three now. the first one changed up the pattern, but it was too late in the year. The second one just reinforced a La Nina type pattern by enhancing Maritime Continent convection. This looked like it would be the big kahuna; percolating down to reinforce an -NAO, it also happened during prime climo. 

Now, I get it, lots of people have always said these SSW aren't much to care about. But I like to watch and figure things out on my own before I come to a conclusion, because you can't explain the hows and the whys of a decision, IMO, unless you have rolled it around in your own mind a few times. One way or the other, this will be the last one I need to watch. I've watched how Isotherm, griteater, Judah Cohen, Bastardi, Amy Butler, Simon Lee, Daniela Domeisen, as well as many people on this board, use and abuse these events and I think I have a feel for how they work, or at least enough of a feel for using them as a hobbyist.

So, if this one doesn't do much for MBY, or really any of our back yards, I'm not sure they're worth looking at anymore. If we have this "grand conjunction" of a SSW and -NAO in prime climo during an el Nino, I might watch it again, but otherwise, this one has until early Feb to show something. I took a month during the "good" event in 2018 and I'll give this one that long. 

 

This is my first real -NAO as someone who posts on these boards, so that teleconnection has quite a bit more leeway, in terms of how I think it helps or hurts, but so far it seems kinda meh. Maybe the pattern would be worse without it, but even the MA and the normal CAD areas can't get a Miller B that warm noses east TN. 

 

I still stand by what I posted s couple of days ago, for now. And I agree with John, that you can't really care much about what the GFS says past a few days out. But, I despise seeing the "Flood in February" pattern start to show up. I'm over it. I think I'd rather have a severe pattern at this point than what the 0z ensembles are showing:

QPF firehose signal starting to show up:

GEFS

gfs-ens_apcpn_us_64.png

 

CMC enselbles

 

gem-ens_apcpn_us_64.png

 

EPS:

bxFQCmD.png

 

 

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Not sure that the pattern simply doesn't revert back to the pattern that we had during the last 1/3 of December.  During years where La Nina winters are cold(there are some warm ones as well if the Nina is moderate to strong), the cold stretches from the Mountain West to the southern Apps and/or MidWest.  Starting to see the end of the month ridge get pushed back - no surprise.  I think right now we have an unfavorable Pacific battling the NAO.  So far, that has produced four sub-forum events since early December.  I have no crystal ball, but I suspect we continue to see chances through at least the first week of Feb.  Interestingly, wx Modeling actually has been correct about the warm-up which was predicted for January.  TRI is a whopping +4.2F for the month so far and only two days with BN temps.  That said, Kingsport has received roughly 4" of snow during that time frame.  That is what a -NAO does, even if it doesn't have a ton of cold.  NAOs often produce the right confluence combination here.  It is almost as if 89-90 and 95-96 are battling it out.  

As Holston noted, we should be cautious in embracing any dry spell.  It may happen, but when modeling shows abundant cold with no precip - very unlikely that combination occurs due to a very active precip pattern.  Pretty much each time that we have seen a cold front, frozen precip has followed.  So, I think the key is to identify cold air(even if marginal).  That cold, in conjunction with a very active southern stream, has the potential to produce wintery precip for the area.  Some years we get cold, and don't have an active southern stream...hence the phrase cold and dry.  This year just seems the potential for cold and precip to merge is much higher.  That is likely due to the NAO slowing systems down over this region.

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3 hours ago, John1122 said:

Good write up by MRX this morning about the potential for snow Friday night into Saturday morning and how models are very possibly underdoing the precip that falls as snow. MRX also mentioned there will be no temp issues and all areas will see frozen that see precip.

 

 

Good catch. interesting setup this weekend with two drivers for NW snow.  Models look cold too so ratios could squeeze a lot out.  GFS is pretty bullish with QPF across the upslope areas this weekend.  Not super common to see a global this aggressive with straight NW flow atleast in the few winters I've really paid attention.  Maybe we can squeeze out a decent event below the 3500 mark.

In fact, the UK, CMC, GFSv16 all mirror this look and amounts as well. Interested to see the NAM family as they come into range. I bet the 3km pumps out some ridiculous kuchera totals for the high peaks like it always does.

 

snku_acc.us_ma.thumb.png.55fc80019e25522246eac0d27def9982.png

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1 hour ago, Holston_River_Rambler said:

This is the third of these SSW I've watched and I have to say, if this one doesn't do much, it will be the last one I care about. I've seen three now. the first one changed up the pattern, but it was too late in the year. The second one just reinforced a La Nina type pattern by enhancing Maritime Continent convection. This looked like it would be the big kahuna; percolating down to reinforce an -NAO, it also happened during prime climo. 

Now, I get it, lots of people have always said these SSW aren't much to care about. But I like to watch and figure things out on my own before I come to a conclusion, because you can't explain the hows and the whys of a decision, IMO, unless you have rolled it around in your own mind a few times. One way or the other, this will be the last one I need to watch. I've watched how Isotherm, griteater, Judah Cohen, Bastardi, Amy Butler, Simon Lee, Daniela Domeisen, as well as many people on this board, use and abuse these events and I think I have a feel for how they work, or at least enough of a feel for using them as a hobbyist.

So, if this one doesn't do much for MBY, or really any of our back yards, I'm not sure they're worth looking at anymore. If we have this "grand conjunction" of a SSW and -NAO in prime climo during an el Nino, I might watch it again, but otherwise, this one has until early Feb to show something. I took a month during the "good" event in 2018 and I'll give this one that long. 

I have been trying to remind myself while gazing at the long range that we were told a couple of things by these SSW experts:

1. They do not always lead to cold and snow for the eastern US. That said, they can still have a major effect on the pattern, most of us just don't really care if it doesn't deliver(myself included). 

2. Cohen talked extensively about a trickle down effect for us. We are usually third in line on these deals anyway. Siberia/China are first and they had historic high pressure/cold a week ago. Europe is second and I just saw some buried cabins in the Alps and a bunch of crazy snow pics from Madrid. So maybe this shows up by February here.  I think I remember reading there was often as much as a 30 day lead time on effects for us. Maybe we are rushing it?? I get it, even those of us who know better want to see some pretty maps on the ops or ensembles to feel better. :)

 

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2 hours ago, Holston_River_Rambler said:

This is the third of these SSW I've watched and I have to say, if this one doesn't do much, it will be the last one I care about.

 

I feel much the same way.  Finding snow in the south is almost like work as you learn more about the atmosphere.  It was much simpler when I was a kid, before weather models...... All I had to look at was dad's electronic (heath kit) weather station and the sky outside.  It had barometer, wind speed, wind direction, temperature, dew point and wind chill read outs. 

I am interested in the snow shower activity showing on modeling.  The piece of energy rotating through looks good for fairly wide-spread snow showers.  Then we wait to see how much cold we can keep for the following week as moisture builds to our south.  At the very least this winter has been completely different than last winter.

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25 minutes ago, tnweathernut said:

I am interested in the snow shower activity showing on modeling

Yeah me too. Probably some really good lapse rates. 

On a more positive note, just evaluating my own response to the digital snows, I feel like this isn't the first time this season I've seen things look a little bleaker in the long range only to look better as things get closer in time. 

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Got a new toy: GFS Snow growth panels for the weekend system.

giphy.gif

 

I decided to try true weather, since I think they used to have good Ukie precip panels (not as good as what I remembered), data is updated quickly, and they have a good interface. It has some other fun stuff too, just now starting to  play around with. 

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1 hour ago, John1122 said:

Regarding the SSW, it's likely fueling the continued -NAO, which is keeping the SE ridge just enough at bay to keep us from having 0 chance at anything but 60s and cutters. 

Agreed. We would possibly of had a January akin to the Niña 1950 one(a bit extreme but..) if not for the strong -NAO... Too bad the Niña is there or the strength it is.  A weaker, maybe a 95-96 redux or at least a milder version would be great.. better yet , weak to moderate Nino .  If we can keep a decent -Nao, we could still turn some of that projected Feb.  Ark needed scenario to Sled needing.

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I don't consider the 12z GEFS and 12z GEPS ensembles to be particularly warm.  Additionally, the 12z EPS has adjusted post 300 towards the GEFS.  The ridge which was setting up shop in the East in the LR(on modeling a few days ago and had been a mainstay for several days) is now projected to retrograde into the Southwest and create a very typical Nina pattern with cold stretching from Calgary to the TN Valley region.  That ridge at one point was set to connect with the NAO and be quite strong.  Then, it was going to retrograde into the West, but come back East.  As it is right now, we may bet backdoored with BN heights coming in from the Atlantic of all places as the pattern continues to retrograde at our latitude.  While our weather is coming from the west obviously, the 500 pattern is quite another setup altogether.  IMHO, this is potentially setting up concern for an ice storm due to overrunning.  Basically, the cold will periodically surge into this area.  With an active southern jet, the cold will potentially get trapped at some point as WAA overruns it.  You can see very clearly that the 12z Euro operational almost does this.  That has a lot of 95-96 in it.  So, interesting to see modeling yet again pushing back a warm pattern.  BTW, the MJO continues to look better today.  IF the Pacific can be of any support, the East will get cold very quickly as it appears cold is now modeled to enter into western Canada and spread eastward.  The 12z GEFS is a great illustration of this.  Of course, we could get some unwanted Pac air at times, but I would suggest that our source region for cold is about to be quiet cold.  I echo Met85 from the SE forum, great discussion. 

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